A large number of methods have been developed for killing insects, such as termites, in buildings. The most widely used method is tenting the building, then filling the building with a toxic gas for a period of time sufficient to kill termites or other selected insects. This method is effective for killing termites and other insects. However, this method generally requires 12 hours to be effective, requiring building occupants to move out businesses to be closed for approximately a three day period to insure proper venting of toxic material and/or gas. Tenting the building with heavy tarpaulins requires workers to walk and arrange the tarpaulins on the roof, often damaging shingles or other roofing materials. Food and medications must be placed in sealed containers or removed. Generally the entire building must be treated, even if the infestation is localized.
Because of the disadvantages of the toxic gas method, various other techniques of varying effectiveness have been developed, using heated air or very cold air to kill termites, electrical “shock” treatments, irradiation, non-ionizing, etc.
Typical of these is the method disclosed by Charles Forbes in U.S. Pat. No. 4,817,329, in which wood destroying insects, e.g., termites, are killed by applying a heated gas, such as heated air, to wooden surfaces until the building surfaces are heated to a temperature, typically about 120 to 135° F. Temperatures for killing other insects are said to be surprisingly close to this range. This method has been found to be very effective for killing termites. However, this method, using the described temperatures, is not effective for other organisms, such as fungi, and toxic molds such as, but not limited to, aspergillus oryzae, aspergillus terreus, aspergills versicolor, cladosporium hergbarum, stachybotrys chartarum, penicillium aurantiogriseum, pencillium chrsogenum, pencillium glabrum and fusarium oxysporum. Further, many insects such as mites, fungi, molds and the like are a serious health hazard even when dead. Many people are allergic to the dust-like remains of these organisms that can also cause serious health problems. This is a particular problem to persons suffering from asthma, bronchitis, pneumoconious and other respiratory ailments.
Therefore, there is a continuing need for improved methods of killing organisms in enclosures such as buildings that are fully effective in killing and eliminating substantially all such organisms, is non-toxic, can be performed in a relatively short time, is clean, dry and odorless, and removes a large proportion of the dead organisms.